Sewer pipe (and other related buried pipe) defect detection is an important part of pipe maintenance. Sewer lines are configured to prevent leakage into or out of the sewer lines for optimal performance. When defects exist in the sewer pipe, such that leakage can occur, sewer system performance is degraded and the potential for environmental hazards exists. One common method for sewer line defect detection is to pass a video camera through the sewer line and to view interior surfaces of the sewer line directly. A second method for sewer line defect detection is to utilize an electric probe and measure electric current flow through walls of the sewer pipe, to correlate this current through the sewer pipe walls to evaluate electric current flow through the pipe walls, indicative of any defects in the sewer line. Such identification systems are referred to as “electro-scans.”
One common way to deploy a video camera through a sewer line is to provide a vehicle which has an electric signal transmitting cable mounted upon a spool, and typically coupled to a winch which can control the playing out of cable off of the winch and with a camera attached to a free end of the cable. An attached end of the cable opposite the free end receives a signal from the camera (typically through slip rings on the spool of the winch). This camera signal is routed to a camera signal terminal which can provide processing of the camera signal and power a display for viewing of the signal (also generally referred to as a camera signal evaluation station). Other functions performed by the station, functioning as a camera signal processor, can include image data storage. Typically a position encoder is provided adjacent where the cable is played off of the winch which can measure an amount of cable which has been played off of the winch, to correlate camera image data with a position of the camera within the sewer line. In this way, camera image data is correlated and position data within the sewer line can be joined for analysis and interpretation.
Typically a tractor is coupled to the camera within the sewer line or other pipe. The tractor pulls or otherwise advances the camera through the sewer line while the signal cable follows behind and transmits the signal back to the vehicle. A joystick is typically provided at the evaluation station which allows for control of the winch associated with the spool and for tractor control, and also can provide additional features such as pan and tilt features on the camera for more detailed control of the orientation of the camera as it passes through the sewer line being evaluated. To provide all of these functions, the signal transmission cable typically includes a power line, and multiple separate conductors to provide for transmission of separate signals (in other embodiments a two-conductor cable, such as a coaxial cable, suffices). For instance, a camera control signal can pass from the vehicle down to the camera while camera image signal detail can pass on a separate conductive pathway (or the same conductor) back to the vehicle. A power signal can pass along an electric conductor to power the camera for image signal generation as well as to power servo motors to control, pan and tilt operation for the camera and motion of the tractor.
Vehicles which deploy such camera based sewer line (fault) detection systems can be quite elaborate in the features that they provide. For instance, a vehicle can be in the form of a van with a signal evaluation station having large high quality video monitors, high powered computation devices, large spools for signal transmission cable storage, electric power supply for powering of the equipment and other accessories to support the process of deployment and retrieval of the camera and signal transmission cable down into a manhole accessing of the sewer line, as well as to provide a quality work environment for trained technicians to operate the equipment and evaluate signals produced by the equipment. In other embodiments, the vehicle could be a trailer towable by another vehicle.
Electro-scan probe sewer (and pipe) defect identification systems known in the prior art provide useful information as to sewer line performance and the existence of any defects therein. Such electro-scan probe defect detection systems can in many instances provide data which more reliably identifies defects that can leak within the sewer lines and which is complementary with camera data, which is not able to provide accurate predictions of liquid infiltration into the pipe. Beneficially, electro-scan probe based defect detection is not based on an operator visually detecting anomalies within the imaging signal which might represent a defect, but rather the presence of a defect is identified electronically. Thus, a need exists for utilizing the features of camera based sewer defect evaluation vehicles with electro-scan probe sewer defect detection systems.